1. Field of the Invention
The present invention concerns a contact lens case which is provided with a resettable timer for allowing the user to monitor the remaining useful period available for the lenses. More particularly, the contact lens case hereof enables the user to also monitor the remaining useful period for the lens receptacle before replacement of the receptacle is recommended.
2. Description of the Prior Art
Contact lenses are well known optical devices used instead of conventional eyeglasses to improve the vision of the wearer and are placed directly on the wearer's eye. To avoid drying of the eye and resulting discomfort arising from wearing of the contact lens for extended periods, particularly during sleep, it is desirable that the contact lens be removed from the eye periodically. During the periods of non-use, the contact lenses need to be stored in a case to facilitate locating them for reuse, avoiding contamination, and to permit application of antibacterial solutions to the contact lenses. As contact lens technology evolved, the contact lenses were made of more advanced materials to make them less expensive and lighter in weight. As a consequence, these improved contact lenses are typically of a synthetic resin material which are designed to be disposed and replaced after a recommended useful life period.
One reason that the lenses are recommended to be discarded after use over the aforementioned useful life period, typically about one month, is that the synthetic resin of the replaceable contact lenses may accumulate microscopic particles or organisms such as bacteria. While disinfectant solutions may be applied to rinse and limit the effect of these accumulations, the risk of infection or injury to the eye of the wearer increases over time, thus necessitating the replacement of the contact lens at the end of the recommended useful life period.
Various articles have been developed for showing the elapsed period of use for contact lenses and which provide for storage of the contact lenses. These articles are shown in U.S. Pat. Nos. 4,909,382, 5,452,792, 6,038,997, 6,382,409 and 7,042,805, the disclosures of which are incorporated herein by reference. While these various devices are beneficial, they generally require the user to remember and/or recalibrate the device to indicate the useful life of the lenses after replacement of the lenses.
It has also been learned that the storage of the contact lens in the case may result in similar accumulations in the storage case itself. That is to say, some of the microscopic materials and organisms which may be deposited on the contact lenses may then be transferred to and retained by the contact lens case.